Behavioral and epidemiological data indicate that men who have sex with men (MSM) in South Africa have high levels of HIV risk behavior and high HIV prevalence, and experience high levels of stigma, discrimination, and violence in the resource-challenged communities in which they live. The disadvantageous social environment that South African MSM face contributes to their HIV risk behavior and poor sexual health outcomes. A multi-level intervention that will help South African MSM reduce their risk behavior by reducing the impact of homonegative influences in the social environment and increasing individual and collective capacity to effect positive change in their communities is urgently needed. The proposed research project will test the efficacy of Health Empowerment for MSM, a multilevel intervention to reduce MSM's risk for HIV infection in South Africa. Building on a community development and empowerment model found to be effective at risk reduction with MSM in the United States, the intervention will incorporate intensive small-group behavioral workshops to strengthen individual self-efficacy and build social norms for safer sex, and will diffuse these norms through MSM social networks by means of a culturally appropriate peer education program that infuses MSM community events with HIV prevention content. We propose a two-community, multiple baseline comparison of an MSM community receiving the intervention to an MSM community similar in size and social structure where HIV prevention services are primarily provided through local and provincial public health clinics. We hypothesize that after 18 months of intervention, we will observe greater HIV prevention outcomes in our intervention community, relative to the comparison community, with respect to three specific aims: (1) greater levels of social cohesion between members of the MSM community; (2) greater levels of perceived collective power in the MSM community; and (3) greater increases in sexual health-promoting behaviors, including consistent condom and water-based lubrication use with male partners, regular HIV testing among HIV-negative MSM every 6 months, and regular monitoring of HIV disease among HIV-positive MSM every 6 months.